Tertia Clavis Basilii (Basil's Third Key)
Exuret pennas, solvet et ille nives.
Cum sale coelesti sulphur servare memento,
Astutam vulpem gallus ut inde voret.
Ales mersus aquis ad vitam ex igne redibit,
Sentiet atque parem vulpis ab ore necem.
Out of the eagle's stones (e petris aquilae), join the stiff Dragon (rigidum conjunge Draconem): He will burn the feathers (exuret pennas), and he will also melt the snows (solvet et ille nives). Remember to keep the sulphur (sulphur servare memento) with the heavenly salt (cum sale coelesti) in order that (ut inde) the rooster devour the sly fox (astutam vulpem gallus voret). The winged one (ales), dipped in the waters (mersus aquis), will return to life (ad vitam redibit) out of the fire (ex igne), and he will feel (sentiet atque) a corresponding murder (parem necem) by the mouth of the fox (vulpis ab ore).
Here's a close-up that shows the fox, and also shows how there is the alchemical symbol for iron coming out of the dragon's mouth:
You can also read an English rendering of the Third Key here: The Hermetic Museum by E. A. Waite — here is what it says about the fox and the rooster: "then the Cock will swallow the Fox, and, having been drowned in the water, and quickened by the ﬁre, will in its turn be swallowed by the Fox."